3.4 Humans and Ecosystems

What is environmental science?

the study of the interaction between humans and the environment

What is the most important source of environmental change on the planet?

humans

What do human activities do to local and global environments?

human activities change local and global environments

What cycles do humans depend on?

the Earth's nutrient and energy cycles

What is the Earth's energy used to power?

our homes and cities such as phones, streetlights, and cars

Where does everything we eat and drink come from?

the Earth

What can the overuse of resources and the production of waste disrupt?

the energy and nutrient cycles of Earth

What is the current population of humans on Earth?

8.3 billion people

What is carrying capacity?

the maximum population size that an environment can consistently support

What is overpopulation?

when the number of organisms is more than the carrying capacity of the environment to support them

Can the carrying capacity of an environment change?

yes, the carrying capacity of an environment can change as the environment changes

What have allowed Earth to support our increasing population?

technologies that have developed

What are some technologies that have developed that have allowed Earth to support our increasing population?

agriculture, medicine, sanitation

What is ecological footprint?

the amount of land necessary to produce and maintain enough food, water, shelter, energy, and waste

What 3 things does the size of the ecological footprint depend on?

number of resources used, efficiency of resources used, amount of waste produced

What are fossil fuels?

nonrenewable energies

What are two examples of fossil fuels?

oil and coal

Oil and coal currently support the majority of our country's what?

our country's energy use

Why are oil and coal considered nonrenewable?

because they are used faster than they can form

What are renewable energies?

resources that cannot be used up or replenish themselves faster than they are used

What are some examples of renewable energies?

wind, solar, water

If renewable energies are not used carefully, what do they become?

nonrenewable

In what way was Easter Islanders' use of resources unsustainable?

they used up their resources to meet their short term needs

What is sustainability?

meeting needs without compromising the ability of future generation to meet their own needs

Industry depends on the energy that comes from what?

burning fossil fuels like oil, coal, and natural gas

What does burning fossil fuels release?

carbon dioxide

Where does carbon dioxide go after it is released from burning fossil fuels?

into the atmosphere

What does carbon dioxide entering the atmosphere lead to?

a greenhouse effect

How have human activities affected carbon dioxide levels in the atmosphere?

human activities have greatly increased carbon dioxide levels in the atmosphere

How have human activities affected nitrogen levels in the biosphere?

human activities have greatly increased nitrogen levels in the biosphere

What is the effect of altered biogeochemical cycles and climate change?

they threaten biodiversity, human health, and water quality

An increase in nitrogen in the biosphere leads to an increase in what?

an increase in harmful algae

An increase in harmful algae caused by an increase in nitrogen in the biosphere leads to what?

an increase in fish death

Burning fossil fuels, using fertilizers, and other activities can increase the amount of available what in an ecosystem?

nitrogen and phosphorus

An increase in the amount of nitrogen and phosphorus in an ecosystem limits what?

it limits organisms producing these molecules

Limiting organisms that produce nitrogen and phosphorus alters what cycles?

the nitrogen and phosphorus cycles